Miniaturization of robotics is limited by technical progress. An autonomous robot must have a power source, control electronics and power drives, which together determine its weight and size. In the case of flying platforms, the task is complicated by orders of magnitude. Scientists from the USA have found a solution. They moved the power supply and control of the robot outside the platform, creating the world’s smallest free-flying robot.
Image source: UC Berkeley
Miniature robots could one day replace insects in pollinating plants or inspect areas that are hard for larger platforms to reach. A development by scientists at the University of California, Berkeley, described in a recent publication in Science Advances, is the first step in that direction.
The idea of removing engines, power sources, batteries, and control electronics from a flying robot resulted in the creation of a tiny device with a diameter of 9.4 mm and a weight of 21 mg. It is a small propeller with a protrusion similar to a top or a gyroscope. Two permanent magnets in the form of washers with a thickness of 0.5 mm and a diameter of 1 mm are installed in the upper part of the structure.
Image source: Science Advances 2025
The effect of an external electromagnetic field causes the magnets to rotate at a given frequency and in the desired direction. The rotation creates a lifting force that can be controlled remotely. The bumblebee-sized robot can take off, hover in place, and move in all directions without being physically tied to objects on the surface of the lab table.
Equipping the robot with sensors to stabilize its flight and orientation in space will make it more controllable up to practical use. Even today, this is possible with a certain degree of accuracy. Powerful electromagnets placed at the edges of the work area can make such robots move at a given height and in the right direction. However, scientists are only at the beginning of the path to creating robotic insects that have real practical value. This path still has to be taken – and it will not be easy.